There is a conventional radio communication system in which a radio terminal transmits scheduling information including a data size to be transmitted and difference information Ph (Power Headroom) between the maximum transmit power the radio terminal can transmit and the current transmit power to the radio base station. The radio base station is known to determine transmit power of the radio terminal based on the scheduling information and to perform scheduling to control a transmission data rate.
In addition, it is recently promoted to standardize LTE (Long Term Evolution) by 3GPP (3rd Generation Partnership Project), for example. In LTE, a transmission bandwidth (resource block) having a plurality of sub carriers is allocated as an uplink radio resource (for example, see Non-Patent Document 1). Accordingly, in LTE also, similarly to the conventional radio communication system, the radio base station determines the transmit power of the radio terminal based on the scheduling information including the difference information Ph transmitted from the radio terminal and performs scheduling to control the transmission data rate.